The invention is intended for the opthalmology sector of the market, within the area of optical applications of a therapeutic and/or prophylactic nature.
The object of this invention is a device for the protection of healthy eyes, pseudophakic eyes (eyes that have undergone cataract surgery) and/or eyes with macular and retinal degeneration, produced by applying a yellow pigment, or filter, to an illumination system. The device protects the eye from the short wavelengths of the visible spectrum (<500 nm).
Referring to FIG. 1, visual perception is the result of the response to visible radiation in the wavelength range 380-760 nm. In the environment, solar radiation is the main risk factor for vision. The sun emits ultraviolet (UV) rays and infra-red (IR) radiation, which are mainly absorbed by the atmosphere. When the solar radiation transmitted through the atmosphere reaches the Earth's surface, it consists of UV-B rays (230-300 nm), UV or UV-A rays (300-380 nm), visible light rays (380-760 nm) and IR rays (760-1400 nm). Healthy human eyes freely transmit IR rays and those of most of the visible spectrum to the retina, but the cornea and crystalline lens prevent the most reactive wavelengths of the light spectrum (UV-B rays, UV-A rays, and the violet/blue portion of the spectrum) from reaching the retina.
The human crystalline lens changes its transmission properties as it ages by intensifying its yellowish color, thus increasing its capacity to filter out UV and violet/blue light rays. Hence, in persons older than 65 years, ultraviolet light (<400 nm) is not transmitted and the transmission of violet/blue light (400-500 nm) is markedly reduced.
The retina is capable of protecting itself from short wavelengths of light in two ways: through its uneven distribution of photoreceptors, such that there are no photoreceptors sensitive to violet/blue light in the macular depression; and through the actions of yellow pigments in this zone, which also exert a protective effect.
These natural protection systems against the shorter wavelengths of light in the human eye—the crystalline lens and structures of the retina—can be seriously affected by certain diseases and/or surgical procedures:                Cataracts, whose surgical treatment involves the removal of the crystalline lens;        Additionally, it is common to find a pathological ageing process that causes degradation of the retinal structures producing age-related macular degeneration (AMD).        
Both cataracts and AMD can coexist in persons older than 65 years. In this population of elderly subjects, cataracts are the main cause of vision loss, and AMD is the main cause of blindness. In addition, an increase in both these diseases due, among other factors, to our increased life expectancy, can be expected. This translates into a great interest in these diseases and their treatment options in the research field and optics industry.
Several epidemiological studies have evaluated the relationship between cataract surgery and AMD. For example, Klein (Klein R, Klein B E, Wong T Y, Tomany S C, Cruickshanks K J. The association of cataract and cataract surgery with the long-term incidence of age-related maculopathy. Arch Opthalmol 120:1551-1558.2002) and Freeman (Freeman E, Muñoz B, West S K, Tielsch J M, Schein O D. Is there an association between cataract surgery and age-related macular degeneration? Am J Opthalmolm 135(6): 849-856.2003) claim there is a higher risk of developing symptoms of AMD in persons who have undergone cataract surgery.
However, in earlier investigations by Wang (Wang J J, Mitchell P, Cumming R G, Lim R. Cataract and age-related maculopathy: the Blue Mountains Eye Study. Ophthalmic Epidemiol6: 317-326.1999) and McCarty (McCarty C A, Mukesh B N, Fu C L, Mitchell P, Wang J J, Taylor H R. Risks factors for age-related maculopathy: the Visual Impairment Project. Arch Opthalmol 119:1455-1462, 2001) this hypothesis was rejected, possibly because of the less developed technology used for their diagnostic measurements. Techniques such as optical coherence tomography that allow the accurate, rapid and non-invasive follow up of retinal neurodegeneration processes have only recently been introduced. These techniques are essential for establishing the determining effect of the natural pigments that absorb harmful radiations.
Several techniques have also been developed to protect eyes subjected to cataract surgery from short wavelengths of light:                There are several types of filters containing a yellow pigment on the market, yet there is no optimal procedure and/or device to apply these filters to the human eye as a preventive and/or therapeutic measure to replace and/or improve the eye's natural protection        Since the mid-1990s, eyes undergoing cataract extraction have been implanted with intraocular lenses containing a yellow pigment to act as a filter. This option requires surgical intervention with all its risks and difficulties. There is also a large population of subjects who have been implanted with a transparent lens to replace the natural lens during cataract surgery who are therefore devoid of the necessary protection. In these patients, the artificial crystalline lens, lacking a yellow pigment, needs to be complemented with a system to support the yellow pigment.        
Several patents related to the state of this technique have been developed although they differ considerably from the object of the present invention, as described by the following references, all herein incorporated by reference:                An absorption filter for colour exposure systems (U.S. Pat. No. 5,121,030) that, through the use of dyes, improves visibility in conditions of intense luminosity.        A color-enhancing filter and method of use to improve the vision of the human eye (U.S. Pat. No. 6,158,865). This invention includes a filter that improves vision in all conditions of light including extreme ambient light and low illumination levels and includes an adapting ring for the filter.        Special optical filters for certain activities and optical accessories that use these filters (U.S. Pat. No. 6,893,127) to improve the visualization of objects, for example in sports activities.        An optical filter and device, filter that absorbs heat rays, optic fiber and spectacles equipped with this optic filter (International Patent Publication No. WO 99 27397). The filter is composed of a synthetic resin capable of protecting from wavelengths of light in the infrared region.        A method for designing colour filters that improve or modify the colour vision of the human eye and colour filtrating media designed by the method (U.S. Patent Publication No. 2004/075810).        A system and method for applying correction factors related to the environmental conditions (U.S. Patent Publication No. 2006/195278) based on a colour detector programmed by software and/or hardware to counteract environmental conditions.        A protection solution for the treatment of eyes (International Patent Publication No. WO 2005 025575), composed mainly of a viscoelastic fluid or rinse containing substances that, at least in part, filter specific frequencies of light radiation.        A protection and correction device for the human eye that includes a set of filters to protect against electromagnetic radiation and/or corrects visual defects such as myopia or lack of colour vision (German Patent Document No. DE 1 0259 261)        An optical vision system that includes a device for partially reducing the illumination intensity (U.S. Patent Publication No. 2002/113941), as, for example, a surgical microscope, that includes a spectral filter adapted to reduce, without eliminating, the intensity of light emitted from a light source in a specific region of the object (which could be the human eye).        A system for the detection and control of light intensity for ocular and projecting microscope lamps (U.S. Pat. No. 6,299,310, based on U.S. Pat. No. 4,715,704) that allows work at a high level of illumination of the eye under examination and also avoids damage to the eye being examined.        A diffusion plate combined with a microscope lamp (German Patent Document No. 8 808 871) that controls the light emitted by the lamp.        An LED system (light emitting diode) for eye examinations (Italian Patent No. 1 147 092) that may incorporate filters.        A solid phometer—apparatus for detecting eye and optic nerve defects that includes the use of neutral intensity filters.        
These devices differ from the present invention mainly in their purpose and utility since none has been designed to protect healthy eyes, eyes subjected to cataract surgery or eyes suffering neurodegeneration from short wavelengths of light.
Moreover, most of these prior art documents do not refer to the application of a filter to a conventional lamp used to illuminate a work, recreation, or home area; rather they are designed to be used in other contexts (e.g., special-purpose lighting systems, lenses, solutions, etc.)